If you tried to reply to any classified ad other than your own - you can't. Any correspondence is by private conversation only. OR..... If you are trying to use a APP , some APPS won't work with the Classifieds and you will have to use a PC.
I also had the same question. Then attempted to start a conversation with a member and was unable to send?
From a phone app or from a desktop PC? Also, members can set their personal preferences to accept or not accept private messages (conversations). But I'm not sure what kind of a message the sender receives if attempting to send a PM to a member who has chosen to not receive them.
Thanks for the clarification,, as I was getting the same thing after a hiatus from viewing the HAMB,, and I thought it was some form of restriction based on other issue,, Thanks